Dears
I use SRB miner old and new version Heavy - double thread - GPU MSI rx480 g4 - samsung memory - win10pro - before change win10 hashrate is 720H/card but after install new win10 hash decreased to 550H/card
old and new driver is crimson blockchain
any help to restore hash to 720 again??
Note: eth hash is 30.5 dual mining and no problem found on it
I use RX 580 4gb and after heavy i have also only 550hs.
With an RX580, you should be getting a good bit more than 550 H/s. I have RX570s and I get 630 H/s per GPU. This is after I overclocked both core and memory.
i dont know to overclocked core and memory... i am new in mining

Read through all of the information on this website:
https://mining.help/amd-electroneum-mining/It discusses the technical details of modifying your GPU. You'll need to play around with the numbers for overclocking as different specs work for different hardware. If you're new to mining, then this is a good resource for you.